Abstract: 【OBJECTIVE】 The study aimed to identify preliminarily powdery mildew on “Yujinxiang” that is the major variety of melon cultivated in lands overlaid with sands of droughty midregion in Ningxia. 【METHOD】 identification preliminary have completed in this paper based on morphological characteristics conidia, germ-tube, fibrosin bodies, hypha, and conidiophores of melon powdery mildew under light microscope. 【RESULT】 The pathogen of melon powdery mildew on “Yujinxiang” is Sphacelotheca fuliginea. 【CONCLUSION】 Sphacelotheca fuliginea could cause powdery mildew on “Yujinxiang”.